I wish I could have gone to SIGGRAPH but for those of us that couldn’t there is still the internet
Here are the course slides for Physically Based Shading in Theory and Practice http://blog.selfshadow.com/publications/s2015-shading-course/
They have som pretty pictures even if they are hard to understand without attending the talks. Even if “Physics and Math of Shading” is the same as previous year it still is a good introduction to the whole Physically based shading.